A conventional three-dimensional, pleated filter, such as that used in heating, ventilation, and air conditioning systems (HVAC systems), includes a filter media and a cardboard frame. The filter media is typically a flexible nonwoven material, including without limitation thermoplastic, microglass, paper, or fiberglass materials that are held in a pleated configuration by means of a wire mesh. Alternatively the filter media may comprise a self-supporting material that is held in a pleated configuration by means of the structural integrity of the filter media itself. Such self-supporting pleated filter media tends to be expensive. The conventional pleated filter is typically assembled by hand by installing the filter media in the rectangular cardboard or beverage board frame. The cardboard or beverage board frame is often weak and is subject to deterioration in the presence of moisture in the air to be filtered.
Pleated filters are also used in a variety of other applications, including without limitation oil filters, automobile air and cabin filters, industrial intake air filters, water filters, etc., in which the filter media is pleated and held in a pleated configuration by a wire mesh or other means before the pleated filter media is mounted in a frame. Because such pleated filters are intended to be disposable, the cost of manufacturing such pleated filters is an important consideration in their design and manufacture. Using a wire mesh to support the filter media or using expensive self-supporting filter media and using hand assembly of the pleated filter media into a separate frame results in unnecessary costs. Consequently, there is a need for a pleated filter or other three-dimensional filter that does not require wire mesh, adhesives, or an expensive self-supporting pleated filter media and that can be manufactured by an automated process.